Meta

Lise Eliot beats Steven Pinker on sex differences

August 8, 2010

I really want you to read this article in Scientific American Mind on the alleged biological differences between boys and girls, but it’s behind a pay wall. So what I’m going to do is blog the article in multiple installments, starting with the big picture.

The author is a neuroscientist named Lise Eliot (right), and she brings a welcome dose of sanity to a subject I had last encountered in Steven Pinker’s The Blank Slate, a masterpiece of conservative political philosophy masquerading as objective science. (Too harsh?) Pinker is emphatic that, as every parent “deep down” knows, “boys and girls are [not] interchangeable” (422), and anyone who coolly analyzes the evidence must come to the same conclusion. Of course, the evidence he offers is little more than a grab bag of isolated, circumstantial factoids.

In the case of girls v. boys, Pinker’s primary argument for innate differences is the claim that “[c]ontrary to popular belief, parents in contemporary America do not treat their sons and daughters very differently” (350). He backs this up by citing “a recent assessment of 172 studies involving 28,000 children[, which] found that boys and girls are given similar amounts of encouragement, warmth, nurturance, restrictiveness, discipline and clarity of communication. The only substantial difference was that about two-thirds of the boys were discouraged from playing with dolls, especially by their fathers, out of a fear that they would become gay.”

We’ll leave the “discouraged from playing with dolls” doozy for a separate post. The rest is über-scientific, right?

Not according to Eliot, who takes the more systematic approach of examining the developmental trajectories of boys and girls along each dimension of supposed biological difference – reading and writing, math skills, aggression, etc. – to identify points at which culture has likely entered the picture.

Here’s how she summarizes the evidence:

Boys and girls are different, but most psychological sex differences are not especially large. For example, gaps in verbal skills, math performance, empathy and even most types of aggression are generally much smaller than the disparity in adult height, in which the average five-foot, 10-inch man is taller than 99 percent of women. When it comes to mental abilities, males and females overlap much more than they stand apart.

Furthermore, few of these sex differences are as fixed, or hardwired, as popular accounts have lately portrayed. Genes and hormones light the spark for most boy-girl differences, but the flame is strongly fanned by the essentially separate cultures in which boys and girls grow up. Appreciating how sex differences emerge can reduce dangerous stereotyping and give parents and teachers ideas for cross-training boys’ and girls’ minds, to minimize their more troubling discrepancies and enable all children to more fully develop their diverse talents.

Cultural biases may also create sex differences where none existed to begin with. Newsweek’s Sharon Begley gives us a helpful paradigm in her review of Eliot’s 2009 book Pink Brain, Blue Brain:

Among certain parents, it is an article of faith not only that they should treat their sons and daughters alike, but also that they do. If Jack gets Lincoln Logs and Tetris, and joins the soccer team and the math club, so does Jill. Lise Eliot, a neuroscientist at Rosalind Franklin University of Medicine and Science, doesn’t think these parents are lying, exactly. But she would like to bring some studies to their attention.

In one, scientists dressed newborns in gender-neutral clothes and misled adults about their sex. The adults described the “boys” (actually girls) as angry or distressed more often than did adults who thought they were observing girls, and described the “girls” (actually boys) as happy and socially engaged more than adults who knew the babies were boys. Dozens of such disguised-gender experiments have shown that adults perceive baby boys and girls differently, seeing identical behavior through a gender-tinted lens. In another study, mothers estimated how steep a slope their 11-month-olds could crawl down. Moms of boys got it right to within one degree; moms of girls underestimated what their daughters could do by nine degrees, even though there are no differences in the motor skills of infant boys and girls. But that prejudice may cause parents to unconsciously limit their daughter’s physical activity.

Contrast that with Pinker’s claim that boys and girls are treated identically, and then groan at his presumption to speak Truth to the Humanities Department.

6 Responses to “Lise Eliot beats Steven Pinker on sex differences”

I don’t have any strong opinions on Pinker vs. Eliot as you’ve drawn the lines here, but I do have some thoughts on the developmental paradigm.

“Everyone knows” that genes interact with environments to produce outcomes, the question is *how* exactly and what are the implications.

“Culture” unfortunately means too many different kinds of things to generallize about it, and “heredity” is a more extended and less well understood process than we generally acknowledge.

The details are less well understood than most researchers are willing to admit, since we don’t have genetic mechanisms identified yet for the emergence of personality traits, cognition, or intelligence. So the political agendas fill in the gaps.

Yes, the underlying developmental model is the real issue. The problem is that we don’t really know how it works yet, in spite of lots of claims to the contrary. The truth is that all attempts to tie the development of complex traits to either single or multiple common loci have failed. We know statistically that “genes” play a huge role in the differences between people, but the details remain elusive.

However one intriguing thing we do know is that the influence of heredity *increases* over our lifespan. That’s a very provocative fact.

It tells us that environments and cultures don’t differentiate people who start out with inherited traits that define them, and then change. It tells us that in general, environments provide mechanisms for us to express our genes, so to speak.

When Lise says culture fans the flame of genes, her metaphor doesn’t acknowledge the degree to which that “spark” has an ongoing effect throughout our life.

Our genes don’t stop expressing because we reach adulthood, they aren’t just a spark whose influence later becomes irrelevant, they continue to shape our life trajectory.

The identical twin data shows personaity, brain structure, and intelligence all shifting toward heredity over time, the “non-shared environment” is our biological inheritance helping to make us and our environment what we need it to be.

The bottom line is that we tend to grow *into* our inheritance, not out of it, and we are legitimately unsure of the details.

Patrick, C. L. (2000). Genetic and Environmental Influences on the Development of Cognitive Abilities: Evidence From the Field of Developmental Behavior Genetics. Journal of School Psychology , 38 (1), 79-108.

Lenroot, R. K., & Giedd, J. N. (2008). The changing impact of genes and environment on brain development during childhood and adolescence: Initial findings from a neuroimaging study of pediatric twins. Development and Psychopathology , 20, 1161-1175.

That’s an interesting point to bring up. I’m too sketchy on the concept of heritability to have anything useful to say about the studies you cite. One point Sharon Begley has made before is that a trait like verbal intelligence could be heritable because, say, an individual has attractive eyes that encourage people to talk to her from a young age. So heritability need not be incompatible with an environmental influence. It may simply reflect a head start. I admit that for brain structures that argument probably holds less water, but there’s also not a perfect (or much of any?) mapping between brain structure and personality.

My feeling is, as long as you’ve got differential treatment of the sexes, you can’t rule out a large environmental contribution to observed sex differences. Pinker acknowledges as much when he makes the argument for equal parental treatment of boys and girls. In any event, focusing on difference in a culture that devalues any deviation from the norm strikes me as somewhat perverse.

I don’t disagree with you, although I may be thinking of this a little differently.

To me at least it seems reasonably well established at this point that development is not a matter of genetic mechanisms expressing in isolation from the circumstances of our lives, the process is intimately tied to those circumstances, depends upon them, and changes when they change in various ways.

The same developmental process takes on different trajectories in different “environments,” a vague notion and notoriously difficult to exploit, but certainly true.

It accounts I think for the paradox that measureable intelligence for example is so variable across different times and environments in certain respects, yet we can’t figure out a reliable way to force it to bend to our will by trying to control the conditions. I suspect this is the rule rather than the exception for most complex human abilities.

So for me neither is it a matter of us having some sort of big stick that we can use to pound our genes into behaving differently, outside of genetic engineering, which I think is in general fairly risky.

This is too big and too interesting a topic for a blog comment I think, but I appreciate the opportunity to discuss it briefly.

it funny how we accept gender difference in physical attributes like body size- height and mass as being an irrefutable biological proof of genetic difference between the sexes.

obviously, theres a range of genetic possibility within the species that is entirely dependent on environmental practices, nutrition, etc. Few would disagree with that, but most of us accept that men are just bigger than women. fact.

but, when you look at historical data you see that average heights in the US have substantially increased consistently over the past 200 years. attributed to environmental factors. and though avg female height is currently less than avg male height, avg female height in 2010 is taller than avg male height in 1810. The Current tallest living man is 8’3″ the tallest living woman is 8’2″. 1″ difference in the extreme high end of the range compared to a 6″ difference in the avg.

Humans have very low sexual dimorphism and we work so hard at accentuating the few minute differences we have through cultural practices. Why we do it is another conversation, but i see it all the time. Most parents just don’t feed their girls as much, don’t let their girls climb as high, and don’t let them run with boys.